Init

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "anyhow"
+version = "1.0.71"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c7d0618f0e0b7e8ff11427422b64564d5fb0be1940354bfe2e0529b18a9d9b8"
+
+[[package]]
+name = "ascii"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d92bec98840b8f03a5ff5413de5293bfcd8bf96467cf5452609f939ec6f5de16"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "chunked_transfer"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cca491388666e04d7248af3f60f0c40cfb0991c72205595d7c396e3510207d1a"
+
+[[package]]
+name = "httpdate"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4a1e36c821dbe04574f602848a19f742f4fb3c98d40449f11bcad18d6b17421"
+
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "prometheus_gbl_exporter"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "tiny_http",
+]
+
+[[package]]
+name = "tiny_http"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "389915df6413a2e74fb181895f933386023c71110878cd0825588928e64cdc82"
+dependencies = [
+ "ascii",
+ "chunked_transfer",
+ "httpdate",
+ "log",
+]

Cargo.toml

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+[package]
+name = "prometheus_gbl_exporter"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+tiny_http = "0.12"
+anyhow = "1.0.71"
+
+# minimalize size
+[profile.release]
+strip = true
+opt-level = "z"
+lto = true
+codegen-units = 1
+panic = "abort"

src/collectors/mod.rs

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+pub mod time;

src/collectors/time.rs

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+use crate::metric::{Metrics, Metric, MType};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub fn scrape() -> Metrics {
+    let mut met = Metrics::new();
+    let start = SystemTime::now();
+    let since_the_epoch = start
+        .duration_since(UNIX_EPOCH)
+        .expect("Time went backwards");
+    met.metrics.push(Metric::new_val("node_time_seconds", MType::Gauge, since_the_epoch.as_secs() as f64));
+    return met
+}

src/collectors/uname.rs

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+use crate::metric::{Metrics, Metric, MType};
+
+pub fn scrape() -> Metrics {
+    let mut met = Metrics::new();
+    met.metrics.push(Metric::new_val("node_time_seconds", MType::Gauge, since_the_epoch.as_secs() as f64));
+    return met
+}

src/main.rs

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+mod metric;
+mod collectors;
+use tiny_http::{Server, Response, Method};
+use anyhow::{Context, Result};
+
+use collectors::time;
+
+
+fn main() -> Result<()> {
+    let server = Server::http("0.0.0.0:9100").unwrap();
+
+    for request in server.incoming_requests() {
+        if request.method() != &Method::Get || request.url() != "/metrics" {
+            let response = Response::from_string("Not Found").with_status_code(404);
+            request.respond(response)?;
+            continue;
+        }
+        println!("request! method: {:?}, url: {:?}, headers: {:?}",
+            request.method(),
+            request.url(),
+            request.headers()
+        );
+
+        let mut output = String::new();
+
+        output.push_str(&time::scrape().prometheus());
+
+        let response = Response::from_string(output);
+        request.respond(response)?;
+    }
+    Ok(())
+}

src/metric.rs

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+
+pub enum MType {
+    Gauge,
+    Counter,
+}
+
+impl std::fmt::Display for MType {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            MType::Gauge => write!(f, "gauge"),
+            MType::Counter => write!(f, "counter")
+        }
+    }
+}
+
+struct MetricLabel {
+    label: String,
+    value: String,
+}
+
+impl MetricLabel {
+    fn prometheus(&self) -> String {
+        return format!("{}=\"{}\"", self.label, self.value)
+    }
+}
+
+struct MetricData {
+    labels: Vec<MetricLabel>,
+    value: f64
+}
+
+impl MetricData {
+    fn new(value: f64) -> MetricData {
+        return MetricData {
+            labels: Vec::new(),
+            value: value,
+        };
+    }
+    fn add_label(&mut self, label: String, value: String) {
+        self.labels.push(MetricLabel{label: label, value: value})
+    }
+    fn rounded_val(&self) -> String {
+        if self.value.fract() == 0.0 {
+            return (self.value.trunc() as i64).to_string();
+        }
+        return self.value.to_string();
+    }
+}
+
+pub struct Metric {
+    name: String,
+    mtype: MType,
+    data: Vec<MetricData>
+}
+
+impl Metric {
+    pub fn new(name: &str, mtype: MType) -> Metric {
+        return Metric {
+            name: String::from(name),
+            mtype: mtype,
+            data: Vec::new()
+        };
+    }
+    pub fn new_val(name: &str, mtype: MType, value: f64) -> Metric {
+        return Metric {
+            name: String::from(name),
+            mtype: mtype,
+            data: vec![MetricData::new(value)]
+        };
+    }
+}
+
+pub struct Metrics {
+    pub metrics: Vec<Metric>,
+    pub processtime: f64
+}
+
+impl Metrics {
+    pub fn prometheus(&self) -> String {
+        let mut type_section = String::new();
+        let mut metric_section = String::new();
+
+        for m in &self.metrics {
+            type_section.push_str(&format!("# TYPE {} {}\n", m.name, m.mtype));
+            for d in &m.data {
+                let mut labels = String::new();
+                for (i, l) in d.labels.iter().enumerate() {
+                    labels.push_str(&l.prometheus());
+                    if i != d.labels.len()-1 {
+                        labels.push(',')
+                    }
+                }
+                if labels.is_empty() {
+                    metric_section.push_str(&format!("{} {}\n", m.name, d.rounded_val()));
+                } else {
+                    metric_section.push_str(&format!("{}{{{}}} {}\n", m.name, labels, d.rounded_val()));
+                }
+            }
+        }
+
+        return type_section+&metric_section;
+    }
+
+    pub fn new() -> Metrics {
+        return Metrics {
+            metrics: Vec::new(),
+            processtime: 0.0
+        };
+    }
+}